RC 127 is just the result code from the failing command - you cannot interpret it without first knowing which command set the result code.

The first step is to find the actual error message produced by the cron job. If the standard output and error streams of the cron job have not been redirected, the error messages will be sent by email to the user owning the cron job. If the email services on the system are in default configuration, you will usually find the cron job errors in the user's email inbox, normally located at /var/mail/<username>.